I have a condo in Bangkok, but no longer live in Thailand. The rent goes into my Thai bank account. Am I liable for Thai tax?

Yes

 

Income earned in Thailand is subject to Thai income tax

Thanks for that. Do you know the rate of tax?

http://www.rd.go.th you find info on personal income tax in Thailand, I believe ad a foreigner you must pay tax on income from on local sources. Maybe you must pay the local rental tax of 12,5% on rental value to local or bor tor, under the land and building tax laws. Other, I don't believe many pay any form of income tax under the Thai tax income system, but you can declare rental income in Thailand where you pay tax, there is likely a tax treaty between Thailand and your country and you don't have to pay personal income tax in Thailand, but I am guessing, I am not a tax specialist.

We pay every year 3950 THB to tesseban a fixed amount.

There's a school of thought that says this is why at least some owners don't want to have anything to do with TM30s, even though that's nominally an owner rather than a renter responsibility. The TM30 isn't a tax document per se, but paints a property on the govt radar as being income-generating; there's usually (always ??) a lease agreement involved with the application.

Thank you, folks. That is quite helpful.

12% of gross